Turbine.



G. A. PARSONS & G. STONEY.

. TURBINE.

. APPLIOATION FILED 0012's. 1006.

Patented Sept. 22, 1908.

MTE STATES PATENT carton.

CHARLES ALGERNON PARSONS AND GEORGE GERALD STONEY, OF NEWCASTLE-UPON-TYNE, ENGLAND; SAID STONEY ASSIGNOR TO SAID PARSONS.

TURBINE.

Specification of Letters Patent.

Patented Sept. 22, 1908. 1

Application filed Octobera, 1906. Serial No. 337,966.

ings and especially to the fluid packings of blades. I In order to reduce the clearance necessary in turbines and to reduce the chances of damage by contact due to distortion, strips with their edges projecting towards the o posing member have been secured to t e blades, these edges being adapted to wear when contact takes place.

The objects of the present invention are to provide means to (1) reduce the tendency ofturbine or compressorblades to damage them-: selves or the casing orspindle or to stri ping of blades taking place on account of too c osecontact between the blade ends and the cylinder or drum especially where tightness is secured by small clearances between the blade tips or bladeshrouding and the cylinder or drum, and (2) reduce the skin friction between the blade ends or shrouding of the blades and the surface of the cylinderor drum which in the case of steam turbines may be caused by the presence of water from the steam. or from water of "condensation lying between the fixed and moving surfaces of small clearance. The invention consists in forming the ends of the blades with narrow edges or in pro-- viding on the blades or the casing or drum, strips of serrated cross section so that if too close contact takes place between a fixed and a moving part very. narrow edges only are subjected to the wearing action whereby the tendency to damage or stripping and the losses due to skin friction are reduced.

According to onemethod of carrying the invention into effect, the end of the'bladeis sharpened or brought to a thin edge by grinding, milling, filing, stam ing, taperdrawing or other means. The b ade may be chamfered off .on the concave or convex sides and the 'chamfer may be straight or curved, preferably a concave curve so as to allow, if desired, a greater amount of wear before the thick part of the blade is reached, the thin edge being thereby better preserved. By this method greater security against damage to the blade is obtained should the cylinder or shaft become distorted or the bearings of the shaft Wear or become out of line with the bore; and also the area of blade and surface moving at high velocity and in close proximity relative to the cylinder or drum is much reduced and the skin friction from water thereby reduced.

According to another method of carrying the invention into effect, serrations are rovided on a brass orthe like shrouding o the blade member or on a separate brass or the like striplfixed on the cylinder or drum 0' posite to t I serrations consisting of thin metal edges of small thickness compared with their pitch.

These serrations preferably lie in the circumferential direction-but maybe oblique. like a screw, the obliquity being referably such' a direction as to assist t e flow away of,

The projections may {80.

water to, the exhaust. also be continuous or more or'less discontinuous. They may be formed on the blade shroudin before or after attachment to the blades. en attached to the cylinder or drum the strips carrying the thin metal serrations or edges are inserted separately in giooves and calked or otherwise removably ed' therein. I

- Referring now to the accompanyinfg Figure 1 is a horizontal section through aturbine blade, Fig. 2 rergesents six modified sections on the line A of Fig: 1. Fig. 3 is a detail sectional view of a turbine spindle and in which a serrated strip of brass or Accordin to the forms of section shown in Fig. 2 the b ade is'in, or, shown thinned at the end by fullering out on both sides; in b, thinned by fullerin on one side only, while the form 0, shows t e fullering on the opposite side. In the case of d, the thinning 210- cording to this invention is effected by making an inclined edge on. both the concave and convex sides.

e blade ends,- the projections o the draw I 'ings which form part of this speci cation. 90

' next.

" fixed on the turbine drum or spindle.

' ters Patent is:

' convex form on either side of the blade and that many other forms. of thinning may be adopted. I T

In Fig. 3, the moving blades, 9 are secured in the turbine spindle, j, in any well known manner, as for instance by insertin them in grooves in the carrier and then ca ing in a distance iece, s, between each blade and the T e' fixed blades, h, are-similarly see cured to the casing,7c. Opposite the blades, 9, there are. rovided serrated strips, m, of brassv or the like, fixed in the casing,.while opposite the blades, h, 'a serrated strip, p,'his '1 e strip, p, may be of the same form as the strip, m, in the casing or it may be made wider and be held in position by calkingthe distance piece, s, over it. When these strips are worn out they may be readily replaced.

- Fig. 4 shows a form in which the blade shrouds 'n, are serrated as well as the strip pieces, p and m.

This invention is applicable to turbines and rotary com ressors working with steam,

air, gas or any uid.

Having thus described our invention what we claim as new and desire to secure'by Let- 1. A turbo-machine blade of decreasing commencing a short distance, from said end.

2. A turbo-machine blade thinned onlyiat the end remote from the member which carries it.

3. A turbo-machine blade thinned toan edge at the end only which comes opposite to the drum or casing.

4. A turbo-machine blade chamfered at the end remote from the member-which carries the blade. 1

5. Aturbo-machine blade chamfered on one side to form an edge at the end remote from the memberwhich carries the blade.

6] A turbo-machine blade chamfered on both sides-to form an edge at the end remote from the member which carries .the blade.

7. In a turbo-machine, a packing strip having a finely serrated surface. v

8. In a turbo-machine, a packing strip being reduced in cross section. I

10. A turbo machine blade of uniform width throughout its length but of reduced CHARLES ALGERNON PARSONS. GEORGE GERALD savoury.

Witnesses: V

HENRY GRAHAM DAKYNS, Jr., FREDERICK GORDON HAY BERSFORD. 

